The Blues' defensive fragilities were on display as they suffered a 3-0 defeat at Bramall Lane.
"It was certainly one of our worst days of the season in terms of performance and you get what you deserve on that front," Lampard said, via Goal. "Defensively, we have to absolutely focused on the games ahead.
"I would love to have consistency in the back four, or back two or three or whatever you want to call it. That is what you strive for. Unfortunately this season we have made mistakes and individual errors where you end up striving for it.
"That is the position we are in. The only way out of it is hard work with the individuals involved to get through this season as we're still in a good position considering the expectations at the start of the season, then we'll look forward.
"Amongst other things. You don't want to concede that amount of goals. There are many reasons for those goals when we look through the season. Sometimes I bemoan the fact we don't score enough, that gives you the feeling of comfort in games and nervousness can create problems that lead to goals.
"We know we have made too many errors in terms of giving goals away and it is something that we have to address."